Possible Clues:

• Seaman, one at home on the water
• First Englishman round the world
• Francis put garden tool at bottom of shed
• Sir Francis of the high seas
• Male water-bird
• Man leaves plant liable to poison bird
• Elizabethan circumnavigator
• Des Moines university
• Male duck - circumnavigator
• First Englishman to sail round the world